Unfortunately, cutting fins (also known as "grooming") is a practice used to achieve perfect form without dealing with rigorous selection for many generations. Below is a video detailing the process. Warning: it is uncomfortable to watch.

The IBC and Bettas4All DO NOT condone fin cutting or artificial alteration in any form. It is considered a cruel practice and is not tolerated in any show fish. The only time cutting fins is considered acceptable is if the fish is suffering from fin rot and cutting off the damaged and diseased tissue would help it heal (think surgical removal of gangrenous parts) or if the fish is so overburdened with finnage that cutting it to relieve weight bearing would improve their quality of life.